Table 4.

GRADE assessment for outcomes reported in RCTs on collagen vs. standard of care for chronic wounds.

Outcomes	No. of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	No. of patients		Relative effect (95% CI)	Certaintya
								Collagen	SOC
Wound healing rate	11	RCT	Seriousb	No	No	No	No	484	473	RR = 1.53 (1.33, 1.77)	⊕⊕⊕○ Moderate
Healing velocity	2	RCT	No	No	No	No	No	171	166	MD = 2.69 (0.87, 4.51)	⊕⊕⊕⊕ High
Recurrence of ulceration	3	RCT	No	Seriousc	No	No	No	114	53	RR = 0.47 (0.27, 0.79)	⊕⊕⊕○ Moderate
Adverse events	7	RCT	No	No	No	No	No	281	274	RR = 0.67 (0.44, 1.01)	⊕⊕⊕⊕ High

RCT, randomized controlled trial; MD, mean difference; CI, confidence interval; RR, risk ratio; SOC, standard of care.

^aGRADE Working Group grades of evidence: High quality = we are very confident that the true effect lies close to that of the estimate of the effect.; Moderate quality = we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different; Low quality = our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect; Very low quality = we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

^bDowngraded one level for concerns with performance bias.

^cDowngraded one level for I² > 50%.